Automobile manufacturers typically produce several different types of vehicles, such as sedans, minivans, SUV's, etc., each often having a different steering wheel. Several different reasons for making different steering wheels exist and may include cosmetic considerations such as styling or simply a desire to distinguish one vehicle model from another. However, designing a variety of different steering wheels can significantly increase a manufacturer's cost. This increased cost results from the fact that, in order to protect a driver from serious injury in the event of a collision, each steering wheel design must be carefully engineered to have a desired force/deflection characteristic.
Current designs for steering wheels typically involve the use of a cast armature, made of aluminum, magnesium or an alloy of aluminum or magnesium to supply the structural component, and a variety of cosmetic finish techniques, injection molding, reaction injection molding, etc., to apply an overmold component.
Traditionally the design of the armature has been predicated upon the final appearance of the steering wheel assembly itself. If the steering wheel is styled for a three spoke design, then the structural component of the steering wheel, i.e., the armature, will have three spokes. Likewise, a four spoke steering wheel will have a four spoke armature.
Accordingly, current design practice dictates that a new structural component or armature is required for each newly styled steering wheel. This introduces additional cost into each new program for unique tooling, as well as engineering research, design and development costs. In addition, the performance behavior of each new wheel must be re-validated, both at the component and vehicle level.